A number of different printing devices utilize replaceable toner cartridges. For example, laser printers, multiple function peripheral devices (MFPs), and copy machines have been designed with replaceable toner cartridges that enable a user to quickly and efficiently replenish toner when the device exhausts toner from an existing cartridge. One problem associated with the use of replaceable toner cartridges results when a cartridge unexpectedly runs out of toner while a user is attempting to print documents. Oftentimes, a user is not familiar with how to replace the cartridge, is unwilling to replace the cartridge, or is in a hurry to replace the cartridge because of the need to complete the generation of a document output job. Hence, there has been a need to predict the end of life for consumable products such as replaceable toner cartridges, and several techniques are presently known in the field for indicating to a user the need to replace a toner cartridge.
One problem which has previously been addressed involves determining the use state, i.e., whether a toner cartridge is new or used, of an existing toner cartridge. Both laser printers and copiers have implemented use state features. Prior solutions for determining use state of replaceable toner cartridges involve active detection of toner level by one of several techniques such as optical and magnetic sensors, fuses, etc. However, these solutions require that additional hardware be added onto the cartridge, and that a print engine also be designed to accomplish the task. The use of these solutions is understood in the art of printing and copying technologies. However, these solutions add complexity and cost to the product.
Recently, customers have desired the ability to manage consumables, such as toner cartridges for laser printers. In order to manage consumables, particularly in network environments, additional information needs to be obtained about operation of the peripheral device, or printer. The ability to determine whether a toner cartridge is new or used has become a vital piece of information when managing consumables. If a printer can detect whether a toner cartridge is new or used, consumable management can be enhanced. Without such ability, information necessary to manage consumables is missing, and usage models of toner cartridges become compromised.
Several recent attempts have been made with existing products to monitor whether a cartridge is new or used. One such technique determines toner level largely by counting pixels utilized during successive print jobs. However, such technique does not provide a feedback solution. Hence, the actual level of toner within a toner cartridge is not physically determined. For example, every time a user removes and reinstalls a toner cartridge, as a result of a jam or some other malfunction, the printer is required to prompt the user in order to ask if a new cartridge has just been installed. Assuming the customer answers correctly, the printer is able to correctly count pixels to determine the level of toner remaining with only the added inconvenience of answering being caused to the user or customer. However, if the customer answers this prompt incorrectly, or does not answer at all, then the toner level functionality is rendered inaccurate. Therefore, there exists a present need to provide an improved and low cost technique for accurately monitoring the state of a toner cartridge so that the peripheral device, or printer, has such information available in order to enhance the management of consumables.
Accordingly, there exists a need to detect the state of a consumable, such as a toner cartridge, without adding the expense of active sensing devices, such as sensors and fuses. Furthermore, there exists a need to provide an accurate and low cost technique for determining the operating state of a replaceable toner cartridge in a manner that is not susceptible of operator or user error, or inattentiveness.